Differences in Efficacy and Safety Between Capecitabine and Infusional 5-Fluorouracil When Combined With Irinotecan for the Treatment of Metastatic Colorectal Cancer

Background: Capecitabine is an oral fluoropyrimidine that is shown to have similar efficacy to 5-fluorouracil (5-FU) when used both alone and in combination with oxaliplatin in the treatment of colorectal cancer (CRC). Capecitabine and irinotecan combinations (XELIRI) have been developed for the treatment of this disease but randomized comparisons with standard infusional 5-FU and irinotecan (FOLFIRI) showed conflicting results. Patients and Methods: We searched the literature for randomized controlled trials comparing XELIRI to FOLFIRI for the treatment of metastatic colorectal cancer. Odds ratios with 95% confidence intervals were used to analyze dichotomous variables. Hazard ratios for progression and death were combined with an inverse variance method based on logarithmic conversion. The fixed-effect model and Mantel-Haenszel method were used. Heterogeneity was investigated with the Q-test and l(2.) Sensitivity analyses were performed. Results: Only 3 studies were identified, involving a total of 450 patients. XELIRI was associated with significantly shorter progression-free survival (PFS) and increased grade 3/4 gastrointestinal toxicities such as nausea, vomiting, and diarrhea. Severe neutropenia, however, was significantly more frequent with FOLFIRI. No differences in responses and febrile neutropenia events were observed. Conclusion: Our analysis suggest that the 2 regimens are not equivalent. XELIRI remains an option for the first-line treatment of metastatic CRC but FOLFIRI should be preferred as it confers more benefits in terms of PFS and induces fewer GI toxicities.